ᐅ Possible House Purchase – Air-to-Water Heat Pump Could Become a Money Pit
Created on: 15 Jun 2017 19:31
C
Chris1982_1
Hello experts.
A house that was built solidly three years ago (without insulation) is up for sale.
The house is equipped with an air-to-water heat pump as well as a fireplace. There are no solar thermal or photovoltaic systems.
Heating is provided by the air heat pump and the fireplace, and an energy performance certificate is available. The values have varied somewhat over the three years, but well.
The seller gave me the invoice for the heat pump and the underfloor heating yesterday.
How can I tell if this is a "good" energy concept?
Before I buy, I want to make sure I’m not getting into a money pit.
Do I possibly need the exact external wall thickness (which type of masonry), roof insulation, window specifications, etc. for that?
I would appreciate any information. Have a nice evening and best regards, Chris
A house that was built solidly three years ago (without insulation) is up for sale.
The house is equipped with an air-to-water heat pump as well as a fireplace. There are no solar thermal or photovoltaic systems.
Heating is provided by the air heat pump and the fireplace, and an energy performance certificate is available. The values have varied somewhat over the three years, but well.
The seller gave me the invoice for the heat pump and the underfloor heating yesterday.
How can I tell if this is a "good" energy concept?
Before I buy, I want to make sure I’m not getting into a money pit.
Do I possibly need the exact external wall thickness (which type of masonry), roof insulation, window specifications, etc. for that?
I would appreciate any information. Have a nice evening and best regards, Chris
Let’s take the 8000 kWh and subtract the normal electricity usage, which leaves about 6000 kWh. A good air-to-water heat pump with proper hydraulics has a COP between 3.5 and 4.5. But even with a COP of 3, that would mean a heating demand of 18,000 kWh. That either sounds like a 300 m² (3,230 sq ft) area, a poorly adjusted heat pump, or poor insulation. I would actually be cautious.
C
Chris1982_115 Jun 2017 20:28So, after a quick call with the seller, it turns out his monthly electricity advance payment is actually 210€ (about $225). So your calculation is basically correct.
The house is 198 square meters (2,130 square feet) with no insulation.
Regarding the COP: at A7/W35, heating capacity is just under 10 kW, with a COP of 4.4.
Are these details enough?
It all seems a bit high to me as well.
Can the heat pump be better adjusted (if yes, how and what should I look out for), or is the lack of insulation the limiting factor in the bill?
Thanks for your feedback.
The house is 198 square meters (2,130 square feet) with no insulation.
Regarding the COP: at A7/W35, heating capacity is just under 10 kW, with a COP of 4.4.
Are these details enough?
It all seems a bit high to me as well.
Can the heat pump be better adjusted (if yes, how and what should I look out for), or is the lack of insulation the limiting factor in the bill?
Thanks for your feedback.
What does the energy performance certificate say about the annual primary energy demand?
Not that you should take the values at face value, but if they are far off from reality, I would start to have some concerns...
There is an energy consultation service from the consumer advice center available for a very low fee. Maybe you could take advantage of that and bring all the available facts/documents with you.
The COP sounds reasonable at first glance (practical value or datasheet)?
Not that you should take the values at face value, but if they are far off from reality, I would start to have some concerns...
There is an energy consultation service from the consumer advice center available for a very low fee. Maybe you could take advantage of that and bring all the available facts/documents with you.
The COP sounds reasonable at first glance (practical value or datasheet)?
There are no houses from that construction year without insulation. It might be built with thick aerated concrete blocks that were simply plastered. However, this type of wall construction is also insulated, since the air trapped within the blocks acts as insulation. I wouldn’t consider it uninsulated.
The pump is definitely not properly adjusted, but even with the correct settings, you can expect a high electricity bill.
On a different note: Do you like the house? Is it reasonably priced? Even cheap? Then go for it. If you pay 210 for electricity monthly, that’s 2,520 annually. For energy. With gas for a house that size, you might pay 1,500 plus 800 for electricity, totaling 2,300. So what—there’s always something. Karsten
The pump is definitely not properly adjusted, but even with the correct settings, you can expect a high electricity bill.
On a different note: Do you like the house? Is it reasonably priced? Even cheap? Then go for it. If you pay 210 for electricity monthly, that’s 2,520 annually. For energy. With gas for a house that size, you might pay 1,500 plus 800 for electricity, totaling 2,300. So what—there’s always something. Karsten
How old is the house?
The data you provided seems to be from the specification sheet.
With the building description of the house, you could estimate the heating load. Pay attention to insulation and similar details. Windows are also important.
In some new houses, heat pumps are set up completely incorrectly. This can be fixed.
But first, please provide some information about the house.
The data you provided seems to be from the specification sheet.
With the building description of the house, you could estimate the heating load. Pay attention to insulation and similar details. Windows are also important.
In some new houses, heat pumps are set up completely incorrectly. This can be fixed.
But first, please provide some information about the house.
C
Chris1982_115 Jun 2017 20:48COP is taken from the datasheet.
The primary energy demand is 65 kWh per square meter per year. Thank you for the advice from the energy consultant at the consumer advice center.
The primary energy demand is 65 kWh per square meter per year. Thank you for the advice from the energy consultant at the consumer advice center.
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